Needles are commonly utilized especially by physicians and other health care personnel for various purposes, such as the long and short term intravenous delivery (infusion) and withdrawal of fluids, such as nutrients, blood and blood products for treatment and monitoring of the patient. Scalpels are commonly utilized by physicians and other health care personnel for opening the skin of a patient during surgical and other procedures. During use, both needles and scalpels are at least partly inserted or otherwise disposed and maintained within a patient's body.
Syringes are equipped with a needle having a cannula that are inserted directly into the vein of a patient. This is achieved by first properly aligning the needle with the target vein. Once properly aligned, the needle is pushed (directly inserted) through the patient's skin, and into their vein.
Scalpels are equipped with cutting blades having cutting portions which are inserted directly into the body of a patient. This is achieved by first properly aligning the cutting blade with that area of the patient's body in which an incision (or cut) is desired to be made. Once properly aligned, the cutting blade is pushed (directly inserted) through the patient's skin to make the desired incision.
Once a needle or a blade penetrates the skin, contact is made with the blood of the patient and droplets of blood from the patient remain on the needle or blade after their use. If this patient is a carrier of potentially infective germs in his/her blood, the infection may be transmitted to other people who accidently injure themselves with those needles or blades.
Two pathogenic germs that have been shown to be present in a potentially infective state in the blood and almost all the body fluids of infected patients are the human immunodeficiency virus (HIV) and the hepatitis B virus (HBV). Because of the logarithmic increase in the number of people that carry either of these two viruses, a serious public health problem has arisen. Although the HIV is not capable of withstanding exposure to wide ranges of temperature and humidity changes, it is stable enough in the droplets of blood to remain viable and retain infectivity for more than three days if dried and held at room temperature, and for more than a week in an aqueous environment at room temperature. HBV is even more resistant and remains viable at room temperature for 6 months. Other germs that carry similar potential infectivity include hepatitis C, D and E, different bacteria, mycobacteria and fungi. The enormous amount of used needles and scalpel blades generated by hospitals has to be disposed of in specially designed containers in order to avoid accidental injury with these sharp instruments. The problem remains acute for health care professionals, who, despite the observation of " Universal Blood and Body Fluid Precaution" developed by the Center for Disease Control in 1985, suffer an average of 2,000 needle stick injuries daily in the United States alone. A study was made by the Needle Stick Surveillance Group of the C.D.C. (Centers for Disease Control). Out of 3,978 needle sticks from patients known to be HIV positive, 13 health care workers became infected--roughly 1 out of 300. Thus, from a single needle stick while treating an AIDS patient in an operating room or other environment, the chances are roughly 1 out of 300 that the surgeon, nurse or other individual health care provider will sero-convert and become HIV positive. Also a significant public health hazard exists when needles are illegally used by intravenous drug users, get contaminated with potentially infective blood droplets and are disposed of using improper techniques.
It has been proposed to fight bacterial infection by incorporating and/or binding antibiotics and antimicrobial agents into various medical devices (such as catheters, bandages, implants, ocular inserts and interuterine devices) which are inserted into a patient's body. Once inserted, these antibiotic/antimicrobial agents are released or leeched therefrom for preventing infection. Examples of such devices are the catheters disclosed in U.S. Pat. Nos. 3,598,127 issued to Wepsic (a urinary tract catheter of nonpermeable rubber in which antibiotics,such as neomycin is infused); 4,186,745 (wherein antibacterial substances are infused into microporous polyethylene, polypropylene or polyfluorocarbon polymers); 4,054,139 issued to Crossley (wherein oligodynamic agents, such as metallic silver and other heavy metals are incorporated onto catheter surfaces); and 3,566,874 issued to Shepard (wherein antibiotics and germicides, such as penicillin and cetylpyridinium chloride are infused into a hydrophilic polymer for coating medical appliances). Other examples are disclosed in U.S. Pat. Nos. 4,603,152 issued to Lavrin; 4,642,104 issued to Sakamoto et al; 4,650,488 issued to Bays et al; 4,879,135 issued to Greco et al; 4,950,256 issued to Luthoer et al; 5,013,306 issued to Solomon et al; 5,028,597 issued to Kodama et al; 5,019,096 issued to Fox, Jr. et al; and 5,019,601 issued to Allen.
While being generally useful, in varying degrees, for their intended purposes of fighting infection on a localized level, each of these approaches suffers from one or more of the following disadvantages: (1) they merely involve mixtures and the antibacterial agent is neither chemically combined to the plastic nor slowly released; (2) the antibiotic/antimicrobial substances proposed are effective only against specific bacteria and not against aggressive microbes such as viruses (e.g., HIV and hepatitis); and (3) those disclosures involving bioerodible coatings present the undesirable side effect of also releasing the bioerodible coating into the patient's body with all of the attendant problems that that presents.
Finally, with respect to the present invention, it is noted that none of these disclosures have been directed to either needles (of syringes or otherwise) or to cutting blades (of scalpels or otherwise). Specifically, none of the above disclosures cover coating of metal surfaces.
Commonly-utilized and well-accepted for inhibiting infection is the use of iodine. Iodine is a broad spectrum antimicrobial agent that has bactericidal, fungicidal and viricidal properties. When iodine reacts with aqueous solutions, free iodine, which provides the germicidal effect, is released. While generally inhibiting infective germs over the short term, the biocidal effectiveness of iodine is dependent on, inter alia, how long the contaminant is exposed to it. This is particularly important in the case of HIV and HBV where the iodine is effective only after it remains in contact with the virus for a relatively long period of time (more than 10 minutes). Thus, over the long term, since topically applied iodine is released all at once, it does not provide adequate sustained protection. Further, such topical application is of little to no use in inhibiting internal infection either in the short term or in the long term.
To increase the effectiveness of iodine, it is normally incorporated into solutions, soaps, creams, pastes, etc., to form an iodophor. Such iodophors, in effect, provide a reservoir of iodine from which small amounts of free iodine in aqueous solution are released over a period of time. These iodophors are then topically applied to that area of a patient's body which is desired to be treated. Perhaps the best known of these iodophors is povidone-iodine, a compound of polyvinylpyrrolidone with iodine. An example of such an application can be found by reference to U.S. Pat. No. 4,010,259 issued to Johansson.
It has been disclosed to incorporate iodophors onto various medical paraphernalia for topical application. In U.S. Pat. Nos. 3,235,446 issued to Shelanski et al, iodinated polyurethane foams and films are incorporated into bandages and sponges. Similarly, U.S. Pat. No. 3,401,005 issued to Katz discloses fibrous materials (such as gauze) that are treated with combinations of polymers, halogens and iodine for use in bandages and surgical dressings. U.S. Pat. No. 4,094,967 issued to Gilbert discloses compositions method of binding iodine to polyvinylpyrrolidone with the use of cinnamic alcohol or tannic acid which is to be applied to matting, gauzes and foam rubber for topical use. U.S. Pat. No. 4,113,851 issued to Le Veen et al, discloses a composition of iodine, pyrrolidone polymer and a polymeric basic acid for incorporation into salve-ointments, dressings or bandages. U.S. Pat. No. 5,156,164 issued to Le Veen et al discloses a contraceptive sponge consisting of a polyurethane open cell foam impregnated with surfactant and iodine.
While being useful for their various purposes of generally inhibiting bacterial infection at the point of the insertion over the short term, all of those references disclose compositions into which the iodine has been complexed for topical application only. None of those references disclose compositions that are suitable for coatings for either needles or the blades of scalpels.
U.S. Pat. No. 5,071,648 issued to Rosenblatt discloses films and sponges formed from polyvinyl alcohol complexed with iodine, which provides a controlled release of iodine.
It has also been disclosed in U.S. Pat. No. 4,381,380 issued to Le Veen et al, to provide cross-linked thermoplastic polyurethane articles, such as catheters, into which iodine has been complexed for antibacterial use. While being useful for their purpose, such cross-linked thermoplastics cannot be utilized for coatings. Further, such thermoplastic polymer complexes are not readily suitable for being fabricated into either needles or cutting blades, which are in need of "razor" sharp edges.
As is well-known, polymers, such as polyurethanes, may be either essentially cross-linked or essentially uncross-linked. The uncross-linked polymers are suitable for the production of coatings, but are not of a tensile strength which is acceptable to fashion appliances, such as needles and blades, which require more exacting physical properties. The cross-linked polymers are suitable for the production of appliances, but are not suitable for the production of coatings, such as the ones noted herein. Further, cross-linked polymers possess a steric hinderance that renders inaccessible many, and sometimes all, of the linkages which complex with the iodine.
It would be extremely advantageous to provide either a surgical scalpel having a cutting blade and needles for use with syringes which has a polymer coating that has iodine that will start being released when the needle or scalpel blade come in contact with blood. The iodine is either complexed therein for quick and relative immediate release of the iodine and/or matrixed therein for sustained release of the iodine.
Thus, it can be seen that there remains a need for cutting blades and needles that are solvent coatable with a polymeric dispersion or solution that have iodine complexed and/or matrixed therein, so as to provide for immediate and/or sustained release of the iodine therefrom for inhibiting infection, that is commonly associated with the use of such cutting blades and needles.